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Looking for a sensor or devise, that indicates a forward and a reverse movement

Does anyone know of a devise or sensor that can indicate a signal or no signal for a forward movement, but have a signal for a reverse movement? Or is it impossible to do? I am open to any other solutions that someone can tell me

Description of project is that

1=2E It has a flat surface to mount to 2=2E It has wheels for mobility for the movement of a forward or reverses (push or pull) 3=2E Power supplied 12v DC 20amp 4=2E To be used for out-door use, subject to extreme weather conditions and temperatures.

Example: Take a child's red wagon being pulled or pushed in different directions. Pull the wagon towards you and walk "prefer a signal Stop "prefer a signal Push the wagon backwards "signal " Now pull the wagon towards you and walk "prefer a signal

The specs should fall into this area Sensor Specifications:

1=2E Bi-Directional 2=2E 1-3 phase signal, reverse motion and stationary (non movement) 3=2E Generate a signal reverse or opposite direction from a forward motion 4=2E Time delay adjustment 5=2E Temperature rating -40=B0C - +50=B0 6=2E .5v - 12v DC .01amp 7=2E Sealed unit 8=2E Weather proof 9=2E .002% accuracy
  1. Vibration tolerance adjustment
  2. To be used in an external application only
  3. No moving parts or external reference
  4. Non magnetic
  5. PC programmable

Something like a digital compass? I'm not that experience in this field

Reply to
tecjim
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Looks like homework. Google 'Inertial Navigation'

Dave

Reply to
Dave

Put a rotation sensor on one of the wheels - standard rotation sensors have separate "in-phase" and "quadrature" outputs, which together can be decoded to tell you the direction of rotation of the wheel.

Farnell - and other broad-line distributors - list a wide range of optical rotation sensors based on a fixed LED sources shining through a fixed Moire-grating (fixed to the axle) and a moving grating (fixed to the wheel) onto a pair of fixed photodiodes or phototransistors.

There are also systems for doing the same job based on permanent magnets and Hall sensors, or you can just fix a wheel to the shaft of permanet magnet stepping motor and monitor the back EMF develop in the "in-phase" and "quadrature"coils, though this voltage does depend directly on the speed of rotation of the wheel.

--=20 Bill Sloman, Nijmegen

Reply to
bill.sloman

Reply to
tecjim

Try bottom posting next time - that is the conventional style in this group.

Have you though about the global positioning system? It throws up pretty accurate velocity data as well as position.

Cell phones can also have a pretty precise idea where they are vis-a-vis the local transmission masts, though I don't think that you can get velocity directly.

--
Bill Sloman, Nijmegen
Reply to
bill.sloman

Don't you have to subcribe to a gps provider? If you don't then that would be the answer. This devise is going to be used around the world.

Reply to
tecjim

"tecjim" schreef in bericht news: snipped-for-privacy@k70g2000cwa.googlegroups.com...

GPS is free, but with 10-30 meter uncertainty not accurate enough.

There is an optical mouse on my desk. You just need a bigger version of that?

--
Thanks, Frank.
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Reply to
Frank Bemelman

The satelites are just beacons - anybody can detect the signals.

As a position indicator, GPS doesn't have the absolute accuracy the OP wants, but the frequencies transmitted by the satellites are stunningly accurate, so the OP should be able to use Doppler shift to as a very sensitive and direct absolute velocity indicator.

The frequencies transmitted by the (moving) satellites do have their own Doppler shifts, not to mention significant relativiistic frequency shifts, but this is all very predictable.

Can the OP rely a mouse-pad under the moving machine? An optical mouse can't work on a totally absorbing/completely unreflective surface.

--
Bill Sloman, Nijmegen
Reply to
bill.sloman

schreef in bericht news: snipped-for-privacy@m7g2000cwm.googlegroups.com...

Such surfaces are hard to find. Have not found anything yet that it doesn't like.

--
Thanks, Frank.
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Reply to
Frank Bemelman

...

When I tried optical mice on mirrors and thick sheets of clear lexan, they didn't work. Was your experience different?

-jiw

Reply to
James Waldby

I just tried a mirror - no luck at all. With a piece of

10mm thick plexiglass, it behaves, eh, confused and jumps around a bit. But it works well on very black surfaces and all other stuff around me. 
--
Thanks, Frank.
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Reply to
Frank Bemelman

Andy comments: I've worked on doppler nav sytems that bounced RF off the ground from an airplane and used the doppler to tell speed and direction..

I bet one could bounce ultrasonic off the surface beneath it to achieve the same effect. It might be worth a simple experiment. It would point out at an angle...

I think some boats use sonar to do this at 200 Khz.

... but I'm too lazy to try it myself..

Andy in Eureka, Texas

Reply to
AndyS

It's nowhere near as hard as you're making it out to be -

look at an ordinary computer mouse. You could hack one and couple it to the shaft with a rubber band.

You will need some sort of discrimination circuit - I think you can do this with a few gates and a couple of flip-flops.

Good Luck! Rich

Reply to
Rich Grise

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